I bought the four side jar for my mixer because it was shipped with the larger wild side jar. I use it primarily for smoothies and didn't need that much volume. With my four side jar I now make my smoothies perfectly every time. I have now even begun to use both jars simultaneously for large prep. It's great. I use the big jar to break down and juice a watermelon and then the small jar is ready for the juice I made to make the base for a smoothie
I've had this product for over 10 years and I just recently had to replace the cup because I couldn't take the blade and the cup a part. The blade even after this many years chopped like it did the first day I got it. I'm sure I can take it somewhere and have them take the blade out and replace the rubber seal on the bottom. But rather than trying to find a place to get the cup fixed I just got a new one, because I know that it will last me at least another 10 years if not more.
Bought this about 3 years ago. After about 300 uses, it started leaking at the bottom. Blendtec replaced as it really shouldn't have failed in that short of period. I have well over 1,000 uses on the second jar and it is holding up perfectly. This is by far the best blender. I make smoothies and veggie drinks in and it really works.
I love my Blendtec. I just replaced my jar. Looking forward to more years with my machine. If/when it fails, I will by another. I actually make vegetable drinks more then sweet smoothies. I can get the WHOLE vegetable. Much better than juicing.
I got my Blendtec as a Father's Day gift over three years ago and we love it. We did have to recently replace the Fourside Jar because we use it everyday. My wife & I start each day with a custom smoothie full of Kale, frozen blueberries and other trendy "good for you" stuff. It's filling and I feel I started my day right, which inspires me to "behave" the rest of the day. Sometimes we take frozen bananas, a little almond milk or dare I say half-n-half, and wow, what a treat.
We bought a K-Tec Blender several years ago, its only weakness was the jar wouldn't last long without leaking around the gasket. We bought the Blendtec square jar to replace our latest leaker. It works very well and we are pleased with it. We do hope, however, that it will last longer than our old jars. It is after all very costly to replace a jar if it isn't under warranty.